1. Field of the Invention
The present invention relates generally to magnetic heads and, more particularly, to a multilayered ferromagnetic laminate having alternating cobalt alloy and iron-nitrogen alloy films deposited upon one another for use as shield or pole material in magnetic disk and tape heads.
2. Background Art
Materials used as magnetic sensor shields and inductive write poles in magnetic transducers such as magnetic disk and tape heads require a variety of optimized physical, electrical, and magnetic properties to assure proper performance. These optimal properties include soft, stable magnetic properties, proper wear, high magnetic moment, and corrosion resistance. High frequency write capability is required for write pole materials.
A high saturation magnetization and high permeability alloy for the write pole of a magnetic transducer provides high density recording, especially with respect to the ability to write to high coercivity recording mediums.
The magnetic film structures may be constructed from a laminated structure having a plurality of magnetic layers as disclosed in U.S. Pat. No. 4,610,935. This patent describes a laminated thin film structure having a plurality of magnetic layers containing iron or cobalt (Co) as the principal constituent and an intermediate very thin layer of a nickel-iron alloy or an amorphous magnetic alloy. A plurality of the laminated layers can be placed together separated by a nonmagnetic isolation layer. Nitrogen (N) is not included as a component of any of the layers.
U.S. Pat. No. 4,748,089 describes a magnetic head having at least a portion of its pole pieces formed of a multilayered laminate of main and spacer magnetic films. The main magnetic film is a binary system amorphous alloy with its principal constituent being a material selected from the group of cobalt, iron, and nickel. The spacer magnetic film is made from a polycrystalline or amorphous ferromagnetic material. Nitrogen is not included as a component of either magnetic film.
U.S. Pat. No. 4,858,049 describes a magnetic film having ferromagnetic layers of nickel and iron alternated with a layer of iron and nitrogen which is an element that is interstitially soluble in the iron.
U.S. Pat. No. 5,264,981 describes a multilayered ferromagnetic film having alternating layers of iron-nitrogen and nickel-iron-nitrogen alloys. The iron-nitrogen layer is an iron alloy having an element of up to ten atomic percent taken from nitrogen. The nickel-iron-nitrogen layer is a nickel-iron alloy ranging from thirty to hundred atomic percent of nickel with a nitrogen doping. The nitrogen doping level is greater than zero and up to ten atomic percent in nickel-iron.